21652809415172 has 12 divisors (see below), whose sum is σ = 40807217744076. Its totient is φ = 9993604345440.

The previous prime is 21652809415129. The next prime is 21652809415189. The reversal of 21652809415172 is 27151490825612.

It can be written as a sum of positive squares in 2 ways, for example, as 5657481074116 + 15995328341056 = 2378546^2 + 3999416^2 .

It is a super-2 number, since 2×21652809415172² (a number of 27 digits) contains 22 as substring.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 208200090479 + ... + 208200090582.

It is an arithmetic number, because the mean of its divisors is an integer number (3400601478673).

Almost surely, 2^{21652809415172} is an apocalyptic number.

It is an amenable number.

21652809415172 is a deficient number, since it is larger than the sum of its proper divisors (19154408328904).

21652809415172 is a wasteful number, since it uses less digits than its factorization.

21652809415172 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 416400181078 (or 416400181076 counting only the distinct ones).

The product of its (nonzero) digits is 2419200, while the sum is 53.

The spelling of 21652809415172 in words is "twenty-one trillion, six hundred fifty-two billion, eight hundred nine million, four hundred fifteen thousand, one hundred seventy-two".